Predictors of early failure and secondary patency in native arteriovenous fistulas for hemodialysis.

Fistula Salvage by Endovascular Therapy

Risk factors for early arteriovenous fistula failure in patients undergoing hemodialysis and comparison of diagnostic prediction models.

Background Arteriovenous-fistula (AVF) are crucial for hemodialysis access, yet they frequently experience early failure. While studies have identified potential patient and clinical risk factors, these findings remain inconsistent. This inconsistency might be attributed to the varying definitions of “early failure”. Our retrospective cohort study aimed to evaluate how common risk factors predict four frequently early-failure criteria: thrombosis/stenosis, <500 ml/min blood flow, <5 mm vein diameter, and ≥6 mm deep vein. We also assessed how well these risk factors predict early failure defined as meeting at least one of these criteria. Additionally, we examined the predictive ability of vein-distensibility, a previously overlooked factor in AVF failure. Methods Consecutive patients with first-time AVF employing standard minimum preoperative artery- and vein-diameters (1.8–2.0 mm) who underwent first Doppler-ultrasound (DUS) at ≤4 months in 2016–2022 were identified. Early AVF failure was defined as the presence of at least one of the following conditions on the first DUS: poor blood flow (Qa), poor vein diameter, poor vein depth, and thrombosis/stenosis. Factors associated with early AVF failure were explored with multivariate analyses. Results 105 patients were eligible and 63 (60%) had an early AVF failure. The only strong predictor of early failure was low vein-distensibility (Odds ratio = 0.57, 95% confidence intervals [CIs] = 0.38–0.83, p = 0.005). Female sex only predicted too-deep veins (Odds ratio = 14.29, 95% CIs = 2.00–100, p = 0.024). Conclusions venous distensibility may be a useful early-failure determinant when minimum preoperative vessel-diameter limits are met. Moreover, the female sex is associated with too-deep AVF veins.

Simple Predictive Model of Early Failure Among Patients Undergoing First Time Arteriovenous Fistula (AVF) Creation

BackgroundGuidance varies regarding the optimal timing of arteriovenous fistula (AVF) creation. The aim of this study was to evaluate the association between uraemia, haemodialysis and early AVF failure.MethodsImmunoblotting and cell proliferation assays were performed on vascular smooth muscle cells (VSM) cells isolated from long saphenous vein samples to evaluate the cells’ ability to proliferate when stimulated with uraemic (post-dialysis) and hyperuraemic (pre-dialysis) serum. Clinical data was collected prospectively for 569 consecutive radiocephalic (RCF) and brachiocephalic (BCF) fistulae. The primary outcome was AVF failure at 6 weeks. Dialysis status (haemodialysis (HD); pre-dialysis (Pre-D)), eGFR and serum urea were evaluated to determine if they affected early AVF failure.ResultsHuman VSM cells demonstrated increased capacity to proliferate when stimulated with hyperuraemic serum. There was no significant difference in early failure rate of either RCF or BCF depending on dialysis status (pre-D RCF 31.4% (n = 188); pre-D BCF 22.4% (n = 165); HD RCF 29.3% (n = 99); HD BCF 25.9% (n = 116); p = 0.34). There was no difference in mean eGFR between those patients with early AVF failure and those without (11.2+/-0.2 ml/min/1.73 m2 vs. 11.6+/-0.4 ml/min/1.73 m2; p = 0.47). Uraemia was associated with early AVF failure (serum urea: 35.0+/-0.7 mg/dl vs. 26.6+/-0.3 mg/dl (p < 0.001)).ConclusionsWe present the first in vivo evidence of an association between adverse early AVF outcomes and uraemia. This is supported mechanistically by in vitro work demonstrating a pro-mitogenic effect of hyperuraemic serum. We hypothesise that uraemia-driven upregulation of VSM cell proliferation at the site of surgical insult in contributes to higher early AVF failure rates.

Five-Year Results of the Valor II Trial of the Medtronic Valiant Thoracic Stent Graft

Vas Q – An Innovative External Support Device Improves Functionality of Arteriovenous Fistulas: Pilot Study Results

Arteriovenous fistula (AVF) is the most preferred vascular access for hemodialysis patients, and early failure of AVF is one of the most avoidable complications of this procedure. We retrospectively evaluated whether adjuvant systemic heparinization just before arterial manipulation could reduce early failure of primary AVF. Three hundred and fifty-six patients with end-stage renal failure who underwent primary AVF surgery from April 2009 to September 2020 were enrolled in this study. The patients were divided into two groups based on whether they received adjuvant heparinization or not. Patient backgrounds, frequency of early AVF failure, and bleeding events were compared between the two groups. Multivariate Cox regression analysis identified risk factors for early AVF failure. Early failure of AVF was observed in only 2 of 157 patients (1.2%) in the adjuvant group, and the incident was significantly lower than observed in the non-adjuvant group, i.e., 17 of 199 patients (8.5%) (p = 0.002). Bleeding events were not significantly different between the two groups. Seven of 157 patients (4.5%) in the adjuvant group and 7 of 199 patients (3.5%) in the non-adjuvant group experienced bleeding events (p = 0.785). Female sex, use of steroids, hypoalbuminemia, venous stenosis in pre-surgical evaluation, arterial spasm in the perioperative period, new-onset venous stenosis after AVF anastomosis, technical failure of surgery, no early cannulation after surgery, and non-adjuvant heparinization were related to early AVF failure in the multivariate regression analysis. Adjuvant systemic heparinization therapy just before arterial manipulation reduced early failure of primary AVF without increasing bleeding events.

Arteriovenous fistula (AVF) patency is important for patients undergoing hemodialysis. The association between early AVF failure and the prognosis, including all-cause mortality and major adverse cardiovascular events (MACE), has not been fully investigated. The present study was performed to investigate the association between early AVF failure and 3-year mortality, cardiovascular disease (CVD) mortality, and MACE. We analyzed 358 patients who started hemodialysis in our institution from October 2008 to February 2020. We defined early AVF failure as cases requiring percutaneous transluminal angioplasty or reoperation within 1 year after AVF surgery. The patients were divided into two groups according to the presence or absence of early AVF failure, and the prognosis of each group was examined. The association between early AVF failure and outcomes (3-year all-cause mortality, CVD mortality, and MACE) was determined using Cox proportional hazards regression analysis. During the 3-year follow-up, 75 (20.9%) patients died (cardiovascular death: n = 39) and 145 patients developed MACE. According to the multivariable analysis, the early AVF failure group had a significantly higher risk of 3-year all-cause mortality (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.09-1.83; p = 0.009), CVD mortality (HR, 1.54; 95% CI, 1.29-2.08; p < 0.001), and MACE (HR, 1.68; 95% CI, 1.25-2.26; p < 0.001). When the patients were stratified by age, early AVF failure was associated with 3-year all-cause mortality in all groups except for the younger group (<65 years of age). Early AVF failure was associated with an increased risk of 3-year all-cause mortality, CVD mortality, and MACE.

Background:The aim of this study was to evaluate the site, early results, and postoperative complications of arteriovenous f istula (AVF) creation procedures for hemodialysis in our clinic.Methods:The hospital records of 384 patients who underwent 411 AVF creation procedures for hemodialysis by the same team at our clinic between February 2008 and January 2010 were included for retrospective analysis. All procedures were performed under local anesthesia with lidocaine. Vasospasm was treated by mechanical dilatation with a probe and topical papaverine.Results:Of our 384 patients, 58.5% were male and 41.5% were female. Mean age was 46 (range 12–72) years. Of the 411 AVF procedures performed, 106 (25.8%) were created at the anatomical snuffbox, 264 (64.3%) were Brescia–Cimino procedures, and 41 (9.9%) were antecubital, brachiocephalic, or brachiobasilic procedures. Twenty-three patients (5.98%) were subjected to more than one surgical intervention due to early thrombosis or failure of AVF. Early patency was found in 94.0% of the AVF created. Twenty-three patients underwent more than one surgical intervention due to early AVF thrombosis or failure. Early AVF failure occurred more often in females (60.8%) than in males (39.2%). Complications were observed in a total of 11.4% patients.Conclusion:Mechanical dilatation of the artery and vein, before starting the anastomosis, as well as the use of vasodilatory agents, could decrease early thrombosis of the fistula, and this method has very high early patency.

The aim of the study was to assess the potential predictive factors for early arteriovenous fistula (AVF) failure following the fistula first initiative. We retrospectively reviewed the data of 159 end-stage renal disease (ESRD) patients who underwent AVF creation. The preoperative factors such as demographic, comorbidity condition, laboratory parameters and medication, and intraoperative or surgical-related factors were assessed. In multivariate logistic regression analysis, significant predictive factors of early AVF failure were female gender (odds ratio (95% confidence interval): 2.63 (1.19-5.81); P = 0.017), higher body mass index (P = 0.038), and lower hemoglobin level (P = 0.048), while adjusting for preoperative factors or all factors. For adjusting of intraoperative factors, reduced venous diameter (P = 0.056) tended to be associated with early AVF failure. In conclusion, female gender, higher body mass index and lower hemoglobin level predicted the occurrence of early AVF failure in ESRD patients.

To study the effect of early cannulation of arteriovenous fistulas (AVF) on early AVF failure. Analysis of two databases of access operations and dialysis sessions from 1/12/2002 till 1/4/2015. Follow-up until 1/4/2016. Functional dialysis use defined as six consecutive cannulations of the AVF with two needles. Early cannulation defined as needling of the AVF within 30 days of creation. Early failure was defined as abandonment for new form of access within 90 days of first cannulation. Machine blood-flow rates (BFR) of each dialysis session for the first 2 months collected from the dialysis database. We analysed 1167 AVFs with functional dialysis use. Some 148 AVFs (11%) were needled within 30 days. Early needling was not associated with increased early failure rates (p = 0.43). Early failure rates were lower in AVFs with six consecutive successful cannulations from the start (p = 0.002). There was a trend of reduced early failure rates (test for trend: p = 0.018) in the latter years of the study period, but no trend in early cannulation rates (p = 0.19). Failure to achieve six successful cannulations from the start was an independent predictor of early AVF failure but early needling was not an independent predictor in multivariate analysis. Average starting BFRs were higher in AVF that were needled early. Early cannulation was not associated with early failure. Failure to achieve six successful cannulations from the start was an independent predictor of early failure. The trend in yearly variation of early failure rates suggests that evolving practices influenced early failure rates.

The first choice of vascular access for hemodialysis in patients with end-stage renal disease is a distal radiocephalic arteriovenous fistula (AVF). Early failure rates for these AVFs vary from 10% to 53%. The effects of predialysis hypotension on failure of AVFs have been described in the literature. Weather lower blood pressures affect early AVF failure has not been extensively studied. We conducted this study to evaluate the effects of preoperative blood pressures on early AVF failure. Ours was a prospective observational study over a period of 2 years that included 224 patients who underwent distal radiocephalic AVF creation. Only those patients were included whose fistulas were made by surgeons with an experience of greater than five cases. The systolic, diastolic, and mean arterial pressures (MAPs) were recorded preoperatively. Early failure was defined as failure to achieve vascular access from the fistula within first 4 months of its creation. The overall early failure rate was 27.7%. Early failure was more common in females and diabetic patients. The systolic, diastolic, and MAPs were significantly lower in patients with early failure (P < 0.05). In a multivariable adjusted analysis, lower preoperative diastolic and MAPs were predictors for early failure of distal radiocephalic AVF. Our study shows that patients with early failure of AVFs have lower preoperative blood pressure. A larger study is required to substantiate our findings and define target preoperative blood pressure for AVF creation.

A significant number of arteriovenous fistulae (28 to 53%) never mature to support dialysis. Often, renal physicians and surgeons wait for up to 6 months and even longer hoping that the arteriovenous fistula (AVF) will eventually grow to support dialysis before declaring that the AVF has failed. In the interim, if dialysis is needed, then a tunneled catheter is inserted, exposing the patient to the morbidity and mortality associated with the use of this device. In general, a blood flow of 500 ml/min and a diameter of at least 4 mm are needed for an AVF to be adequate to support dialysis therapy. In most successful fistulae, these parameters are met within 4 to 6 wk. Most important, commonly encountered problems (stenosis and accessory veins) that result in early AVF failure can be diagnosed easily with skillful physical examination. Recent studies have indicated that a great majority of fistulae that have failed to mature adequately can be salvaged by percutaneous interventions and become available for dialysis. Early intervention regarding identification and salvage of a nonmaturing AVF is critical for several reasons. First, an AVF is the best available type of access regarding complications, costs, morbidity, and mortality. Second, this approach minimizes catheter use and its associated complications. Finally, access stenosis is a progressive process and eventually culminates in complete occlusion, leading to access thrombosis. In this context, the opportunity to salvage the AVF that fails early may be lost. This report reviews the process of AVF maturation and suggests a strategy for when and how to intervene to identify and salvage AVF with early failure.

Hypoxia following arteriovenous fistulization results in venous neointimal hyperplasia(VNH), potentially causing early arteriovenous fistula(AVF) dysfunction. In this study, we used hyperbaric oxygen(HBO) in a rabbit model of AVF to determine whether it could ameliorate early AVF failure. Chronic renal failure was induced by adenine in 96adult rabbits randomly divided into 3groups(n=32in each group). The sham+HBO group underwent sham operation and received HBO. The AVF alone group underwent fistulization, but did not receive HBO. The AVF+HBO group underwent fistulization and received HBO. Each group was further divided into 4subgroups of 8rabbits each that were euthanized at 1,7, 14or 28days post-operatively. At each time point, blood flow changes in the AVF venous segment were detected using a high-frequency duplex ultrasonography system. Immunohistochemical staining for proliferating cell nuclear antigen(PCNA), and hematoxylin and eosin staining were performed to evaluate VNH. Western blot analysis was performed to confirm the expression of hypoxia-inducible factor(HIF)-1α. At 14and 28days following HBO treatment, blood flow in the AVF+HBO group was greater than that at day0. The AVF+HBO group had a smaller ratio of intima to media area, a lower HIF-1α protein expression, and a smaller percentage of PCNA-positive cells in the proximal vein than did the AVF alone group. Our results thus suggest that continuous HBO treatment following AVF significantly inhibits VNH and promotes blood flow. Therefore, early AVF failure may be prevented by the use of HBO therapy.